【作者】 胡萍；

【导师】 ??；

【作者基本信息】 武汉理工大学 ， 车辆工程， 2004， 硕士

【摘要】 本研究论文以摩擦学、高分子材料基本理论为指导，以水轮发电机镶嵌轴承用固体润滑剂为研究对象，进行高分子基复合材料的摩擦学行为的全面研究。经过查阅大量国内外文献资料后确定原料为：聚四氟乙烯树脂为基体，加入石墨、二硫化钼、铜粉、碳纤维等填料；试验方法为：根据均匀试验方法设计配方，用样条函数找出配方与摩擦性能的关系，然后在拟合曲线上选取具有代表性的试验点进行验证试验，达到优化的目的；制备工艺：冷压烧结法制备固体润滑剂。 用SEM表征原料微观结构、摩擦表面及润滑转移膜表面形貌：用XRD进行原料物相分析，及比较水冷却、空气冷却、随炉冷却三种工艺条件下的纯聚四氟乙烯树脂的结晶度；用DSC-TG分析纯聚四氟乙烯树脂及固体润滑剂的热稳定性；用XPS表征碳纤维表面、固体润滑剂摩擦前后表面、润滑转移膜表面的元素组成、价态变化；用销盘式摩擦磨损试验机对固体润滑剂进行摩擦性能测试；采用专用的台架模拟试验机对固体润滑剂镶嵌轴承套与钢轴摩擦副间的摩擦磨损性能进行测定；用莱次偏光显微镜(PM)测试固体润滑剂的硬度；用材料试验机测试固体润滑剂的抗压强度等。试验结果表明： 所选原料的尺寸、形状及纯度可满足固体润滑剂的性能要求；聚四氟乙烯树脂热分解温度超过400℃，但在PTFE中加入无机填料会使复合材料吸水率提高，熔融温度及分解温度降低，且伴有氧化分解反应；碳纤维表面含有C=O及C-O-C等极性基团，有利于提高其与其它组分的相容性，提高层间剪切强度；均匀设计试验方法能够用较少的试验次数找出配方与摩擦性能间的关系，拟合曲线基本能表示各配方的摩擦系数发展趋势；配方中不加铜粉或不加石墨，其摩擦系数均较高，说明铜粉和石墨应该配合使用；当铜粉15份、石墨60份时，铜粉30份、石墨30-40份时，铜粉60、石墨15-30份时，摩擦系数均具有较低值；纯聚四氟乙烯树脂在空气冷却时结晶度最大，磨损量也是三者中最大的；同时，固体润滑剂试样在空气冷却时的磨损量也是三者中最大的：不论是固体润滑剂与45#钢轴配副或是固体润滑剂镶嵌入铜套后与GCr15钢轴配副，在金属表面均可形成润滑转移膜，从而减少金属摩擦副表面间的直接接触，大大延长其使用寿命;转移膜中主要含有较多的石墨、少量聚四氟乙烯、MOO。、FeSO4、CuS等物质;烧结及摩擦均使固体润滑剂表面发生化学变化，使Mo、S、Fe等元素的价态发生变化;纯PTFE的显微硬度最低，固体润滑剂的表面硬度基本是随着填料加入量的增加而增加的;纯PTFE的抗压强度最低，在PTFE树脂中加入无机填料均可明显提高其抗压强度，但并不是加入量越多，抗压强度提高越明显。填料加入过多，不但影响成型加工性(易断裂)，而且影响抗压强度。本研究论文的创新点:1、对聚四氟乙烯树脂为基体的高分子复合材料摩擦学行为进行了较全面的研究;2、根据均匀试验方法设计配方，用样条函数找出配方与摩擦性能的关系，然后在拟合曲线上选取具有代表性的试验点进行验证试验，达到优化的目的;3、通过聚四氟乙烯与无机填料的复合，研制出一种专用于水轮发电机组镶嵌轴承用的固体润滑剂。更多还原

【Abstract】 Based on the basic principles of polymer material and tribology the comprehensive investigation on the tribology behavior of polymer-matrix composite material has been made about solid lubricant used in the embedded bearing for hydraulic generator. After looking up a large amount of native and foreign information, the materials used in the experiment were as follows: PTFE base, graphite filler, molybdenum disulfide filler, copper powder filler, carbon fiber and so on. The experimental method is that the formula was designed according to uniform experimental method, the relationship between formula and frictional property was found with spline function and then the representative test points were chosen from fitting curve to make verification test for optimization. The preparative technique of solid lubricant is cold-press sintering method.The micro-structure , friction surface, lubricant transfer film surface of base material was characterized by SEM; XRD was used to do phase analysis. The degrees of crystallinity of pure PTFE under the different conditions of water cooling, air cooling and furnace-varying cooling were made comparison by XRD. The thermal stability of pure PTFE and solid lubricant was analyzed by DSC-TG; The composition and valence state of elements in the surface of carbon fiber ,solid lubricant before and after friction test and lubricant transfer film were characterized by XPS; The frictional property of solid lubricant was tested by pin and disk test rig . The frictional wear property of solid lubricant between embedded bearing sleeve and steel axle friction pair ring was tested by special simulate test machine, The hardness of solid lubricant was tested by PM; The compression strength of solid lubricant was tested by material test machine.The results indicated that the dimension, shape and purity of base material could meet the functional demand of solid lubricant; The thermal decomposition temperature of PTFE resin exceeds 400 C, but organic and inorganic packing filler added in PTFE made the water absorption rate of composite material increased, melting temperature and decomposition temperature decreased ,in the meanwhile oxidative decomposition reaction was accompanied; Polar groups such as C=O,C-O-C and so on in the carbon fiber surface is advantageous to increase compatibility with other components and interlayer shearing strength; Uniform design experimental method could help to find the relationship between formula and frictional property by relatively small tests .The developing trend ofeach formula’s friction coefficient could be showed by fitting curve; The frictioncoefficient with no copper powder or graphite in formula was relatively big .This fact showed that copper powder and graphite should be used cooperatively; It was found that when the ratio of copper powder to graphite by weight is 15:60,30:30-40 and 60:15-30 respectively, the friction coefficient was relatively small. The degree of crystallinity of pure PTFE reached maximum by air cooling and the abrasion loss also reached maximum among three ones; At the same time, the abrasion loss of solid lubricant sample was also the biggest among three ones; when solid lubricant matched with 45# steel axle or GCrl5 steel axle, lubricant transfer film could be formed on metal surface, thus direct contact between the surface of metal friction pair rings was reduced. Their working life was elongated extremely; There was mainly much graphite, a little PTFF, MoO3, FeSO4, CuS and so on in lubricant transfer film. Sintering or friction all brought about chemical change in the surface of solid lubricant and the change of valence state of Mo, S, Fe and so on; The micro-hardness of pure PTFE was minimum and the surface-hardness of solid lubricant was increased with the increase of additional packing filler in formula; The compressive strength of pure PTFE was minimum and its compressive strength could be increased notably by adding organic and inorganic filler. But not more additional amount, more notable increase of compre更多还原